1. Technical Field
The present invention relates to a piezoelectric element including a lower electrode film, a piezoelectric layer composed of a piezoelectric material, and an upper electrode film, an actuator device including the piezoelectric element that can be flexurally deformed, a liquid ejecting head including the actuator device, and a liquid ejecting apparatus.
2. Related Art
An example of piezoelectric elements used for actuator devices and the like is an element in which a piezoelectric layer composed of a piezoelectric material, such as a crystallized piezoelectric ceramic material, having the function of electromechanical transduction, is disposed between two electrodes: an lower electrode film and an upper electrode film. Examples of actuator devices including piezoelectric elements, i.e., actuator devices that vibrate in a flexural mode, include a liquid ejecting head that ejects droplets from nozzle openings utilizing the displacement of the piezoelectric elements. A typical example of a liquid ejecting head is an ink jet recording head that includes a diaphragm constituting part of a pressure-generating chamber communicating with a nozzle opening for ejection of ink droplets and that ejects ink droplets from the nozzle opening by deforming the diaphragm with the piezoelectric element to pressurize ink in the pressure-generating chamber.
An example of piezoelectric elements used for ink jet recording heads is an element described in Japanese Unexamined Patent Application Publication No. 11-151815, the element being produced by forming a piezoelectric film and an upper electrode film by a film-forming technique on the entire surface of a substrate provided with a lower electrode and cutting the piezoelectric layer and the upper electrode film by lithography into pieces each having a shape corresponding to a pressure-generating chamber.
In piezoelectric elements used for such ink jet recording heads and the like, repeated operations may cause problems, e.g., delamination. Specifically, problems such as the detachment of the upper electrode film from the piezoelectric element layer and the formation of a crack may be caused.
Such problems are present not only in piezoelectric elements used for actuator devices incorporated in liquid ejecting heads such as ink jet recording heads but also piezoelectric elements used for other apparatuses.